Air conveyance system and control

ABSTRACT

A system (method and apparatus) for effecting delivery of a predetermined quantity of lightweight subdivided material to a preselected distribution outlet in a pneumatic conveyance system having a plurality of distribution outlets or stations. The system operates in response to a demand signal from the preselected distribution outlet to initiate a timed sequence of operation of a conveyance blower, simultaneously with movement of flap means adjacent the preselected distribution outlet to divert the conveyance gas and entrained lightweight materials to said preselected distribution outlet. The flap means is held in diverted position by movement of a conveyance gas until such time as the timed blower sequence has been completed. The time period of operating the blower insures delivery of the desired quantity of the lightweight material to the preselected outlet. The control system also includes means to insure continuance of the timed blower sequence with respect to the selected distribution outlet and to prevent interruption of the timed sequence by operation of the control mechanisms at other distribution outlets. The system has utility in the intermittent distribution of subdivided materials (e.g., cushioning and packaging materials, dry cereals, etc.), only upon demand, to a particular filling or packaging outlet, with virtual elimination of blower noise except during the short interval of replenishing the supply at various localized distribution stations.

United States Patent n91 Fuss 1 1 Oct. 2, 1973 22 Filedz 1 1 AIRCONVEYANCE SYSTEM AND CONTROL [75] Inventor: Gunter G. Fuss, Daly City,Calif.

[73] Assignee: Free-Flow Packaging Corporation,

Redwood City, Calif.

Apr. 12, 1972 [21] Appl. No.: 243,237

521 U.S. Cl. 302/28, 141/67 Primary ExaminerEvon C. Blunk AssistantExaminerH. S. Shane Attorney-Paul D. Flehr et al.

[5 7] ABSTRACT A system (method and apparatus) for effecting delivery ofa predetermined quantity of lightweight subdivided material to apreselected distribution outlet in a pneumatic conveyance system havinga plurality of distribution outlets or stations. The system operates inresponse to a demand signal from the preselected distribution outlet toinitiate a timed sequence of operation of a conveyance blower,simultaneously with movement of flap means adjacent the preselecteddistribution outlet to divert the conveyance gas and entrainedlightweight materials to said preselected distribution outlet. The flapmeans is held in diverted position by movement of a conveyance gas untilsuch time as the timed blower sequence has been completed. The timeperiod of operating the blower insures delivery of the desired quantityof the lightweight material to the preselected outlet. The controlsystem also includes means to insure continuance of the timed blowersequence with respect to the selected distribution outlet and to preventinterruption of the timed sequence by operation of the controlmechanisms at other distribution outlets. The system has utility in theintermittent distribution of subdivided materials (e.g., cushioning andpackaging materials, dry cereals, ete.), only upon demand, to aparticular filling or packaging outlet, with virtual elimination ofblower noise except during the short interval of replenishing the supplyat various localized distribution stations.

15 Claims, 5 Drawing Figures PATENTED [1m 2 73 SHEET 10F 3 PATENTED W 2SHEET 3 [IF 3 AIR CONVEYANCE SYSTEM AND CONTROL SUMMARY OF THE INVENTIONAND OBJECTS This invention relates generally to systems forthe rapidconveyance and selective distribution of subdivided lightweightmaterials of the type disclosed, for example, in Fuss U.S. applicationSerqNo. 861,112, filed Nov. 2, 1970.

In general, it is an object of the invention to. improve upon theconstruction of systems of apparatus for such purpose, particularly withrespect to control means making possible the rapid delivery of apredetermined quantity of lightweight material to a. particularpreselected distribution outlet, within a relatively short period oftime.

It is another object of the invention to provide an improved system ofapparatus of such character capable of effecting a timed delivery of apredetermined quantity of lightweight material to a single distributionoutlet, selected from a plurality of such distribution outlets.

It is another object of the invention to provide an improved system ofapparatus of such character wherein the delivery of lightweight materialto the preselected distribution outlet can be locally controlled by anoperator at such distribution outlet.

A further object of the invention is to provide an improved system ofapparatus of such character making use of a blower to effect pneumaticconveyance, wherein the blower operates only during a short period oflocal demand, thus eliminating undesired noise.

A still further object of the invention is to provide an improved methodfor controlling the operation of a pneumatic conveyance system of thetype described, to accomplish the desired result.

Additional objects and features of the invention will appear from thefollowing detailed description of the same, and from the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective of asystem of apparatus embodying the present invention.

FIG. 2 is an enlarged fragmentary view in section, along the line 2-2,of a portion of the apparatus of FIG. 1.

FIG. 3 is a like view showing a different stage in the operation of theapparatus.

FIG. 4 is a view in transverse section along the line 44 of FIG. 2.

FIG. 5 is a schematic representation of an electrical control circuitfor the system of apparatus shown in FIG. 1 through 4.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT In the drawings, the systemof apparatus has-been illustrated as primarily of metallic construction.It is to be understood, however, that any suitable material such asplastic, composition material, or like construction may be employed inparticular embodiments.

Generally stated, the improved system of the present invention makes useof blower means in fluid communication with a substantially closedconveyance system and a source of subdivided lightweight material to bedistributed. In accordance with the invention, the blower is operated ina timed sequence by control means, which insure the selective deliveryof a predetermined amount of the lightweight material to a particulardesired distribution outlet. The control means includes lever means ateach distribution outlet for pivoting gas diverting flap means betweenpositions seal- -ing the outlets and positions interrupting the flow ofconveyance gas in the closed system, whereby the latter can be divertedand dissipated through a particular preselected outlet. The controlmeans additionally includes switch means to initiate a timer control forthe blower and to simultaneously tie-energize the control units at theother distribution outlets. The result is a timed conveyance delivery ofa predetermined amount of lightweight material to the selecteddistribution outlet, based on a relatively short period of operation ofthe blower. Such operation has utility in the short intervalreplenishment of the supply of material at a particular distributionoutlet, with consequent elimination of noise except during the shortperiod of blower operation. A further advantage is that the systemoperates automatically in response to the demand of an operator at aparticular remote distribution outlet.

Referring to the drawings in detail, FIG. 1 illustrates a particularsystem of apparatus in accordance with the present invention. Assuming aplant distribution operation involving the filling of cartons 10 with alightweight packaging and cushioning material 12, the system generallyoperates to feed material from a suitable supply hopper 14 through aclosed conveyance system 16 to various distributionoutlets, generallyrepresented at 18. A source of pressurized conveyance gas, such as theblower 20, is positioned on the inlet side 22 of the closed conveyancesystem 16. Upon demand, the blower 20 functions to continuouslyintroduce air under pressure to the upstream side of the conveyancesystem 16, causing lightweight subdivided material 12 in the hopper tobe drawn into a sub-adjacent venturi section 24 and conveyed through theconduit 26 of the conveyance system. This operation is more specificallydescribed in the aforementioned Fuss US. Pat. No. 3,708,208. As thereindisclosed in detail, the blower functions in cooperation with a screenedhopper outlet 27 to draw lightweight material from the bottom of thehopper 14 into the low pressure zone of the venturi restriction, whereit is picked up and conveyed by the high volume air stream within theventuri restriction.

It is a feature of the present invention that the blower 20 operates toconvey lightweight subdivided materials through the conveyance system16, only in response to an operator demand for such materials at aparticular distribution outlet 18. As particularly illustrated in FIG.'1, the closed conveyance system [6 is proivded with a series of remotedistribution outlets 18, which may be formed of elongate conduitsfabricated of screening material or like gas dissipating means 28. Theelongate screen sections 28 generally provide a visible reservoir fromwhich lightweight materials (viz., foamed, expanded plastic cushioningunits)may be selectively dispensed for use in packaging and cushioningoperations, for example, by valve means 30. At such time as the supplyof packaging or other lightweight materials inthe reservoir 28approaches exhaustion, the operator can signify a demand to replenishthe supply by pulling the lanyard or cord 32 to initiate a controlledoperation of the blower. As hereinafter .described, the blower thenoperates to convey a predetermined quantity of the lightweight materialfrom the hopper 14 to the involved distribution outlet 18.

Referring particularly to FIGS. 3, 4, and 5, each distribution outlet isprovided with a gas divertingflap means 40. The flap means 40 issupported on a pivot shaft 42 and is free to pivot from a normalposition (shown in FIG. 2) where it seals the top or inlet end of thedistribution outlet 18, to a gas diverting position within the conduit26 (shown in FIG. 3) where it diverts the conveyance gas downwardly intothe distribution outlet. As illustrated, each distribution outlet isalso provided with a lever means 44 mounted for pivotal movements on apivot shaft 46 and carrying actuating means 48 slidably engaging theflap means 40. The lever 44 is normally biased upwardly by a spring orother suitable biasing means 50, causing the actuators 48 to assume theretracted position illustrated in FIG. 2. In this position of the flapmeans, conveyance gas is free to bypass the distribution outlet, as itmoves through the closed conduit 26 in the direction of arrow 52.However, upon pulling the lanyard 32 in a downward direction (arrow 54),the lever 44 pivots downward (arrow 56) causing the actuators 48 to moveupward in contact with the flap means 40 (arrow 58) so that the latteris pivoted to the gas diverting position shown in FIG. 3. In thisposition of the flap means, the conveyance gas is diverted downward intothe distribution outlet 18 (arrow 60) where it is dissipated through theupper portions of the screened reservoir 28. Once the flap means 40 hasbeen pivoted to a gas diverting position as in FIG. 3, the conveyancegas exerts sufficient pressure (arrow s 62) to hold the flap means indiverted position, that is, until the timed period of delivery oflightweight materials to the distribution outlet 18 has been completed.At such time, termination of the blower operation enables gravity andthe biasing effect of spring 50 to return the flap means 40 to itsnormal or rest position, shown in FIG. 2.

It is desirable that the operator control the delivery of packagingmaterials or other lightweight materials to the distribution outlet 18.For this purpose, the lever 44 and the pull cord 32 can also form partof control means initiating a timed period of operation of the blower20. Thus, referring again to FIGS. 2-4, gravity type switch means 64 and66 are mounted, respectively, on each of the pivot shafts 42 and 46,with each switch means being keyed to its support shaft for simultaneouspivotal movements. Any suitable gravity type switch means, such asconventional mercury switches, can be utilized for such purpose. Due tothe sliding contact between the actuators 48 and the flap means 40, theswitch means 66 on the lever shaft 46 will shift slightly prior to theswitch means 64 on the shaft 42 for the flap means. The mounting of theswitch means thus provides a slight time delay in the operation of theswitch means 66 and 64. This time delay is useful in initintingoperation of the blower in response to a signal from the particular gasdistribution outlet, just prior to locking out the switching means forsuch purpose at the other gas distribution outlets. Specifically, ashereinafter described, pulling the cord 32 initially shifts switch 66 toenergize a timer control circuit for the blower 20, following which theswitch 64 is de-energized to break or open the control circuits for theother distribution outlets l8.

FIG. particularly illustrates a particular electrical control system toachieve the described control function. As illustrated, power is derivedfrom a conventional power source under control of a main (on-off) toggleswitch 70. Included in the circuit is a suitable motor for the blower,represented at 72, and starter and time delay relays 74 and 76, whichcontrol both the operation and the period of operation of the blowermotor 20. Normally, during a rest condition of the con trol circuit (seeFIG. 5), all of the switches 66 are in the open position so that theforegoing power components are de-energizedv However, upon signifying ademand at a particular distribution outlet, by pulling cord 32, theassociated lever 44 shifts switch 66 to initially close the circuitthrough the normally closed switch means 64 on line 78, to energize thetime delay relay 76 to close switch 80. This in turn energizes thecircuit in line 82 for the starter relay 74, actuating the starterswitch 84 for the blower motor. The blower motor continues to operatethereafter for a timed cycle of operation determined by the time delayrelay 76. In the meantime, the sliding contact of the actuators 48 withthe flap means 40 causes the associated lockout switch 64 to open, thusbreaking the circuit through switch 66 and line 78. All other circuitsremain open because of the normally open position of the switches 66.The net effect on the time delay, obtained by the prior actuation ofswitch 66, is to permit the time delay relay 76 to take over theoperation of the blower motor, so that the blower motor continues tooperate throughout the timed cycle. Releasing the pull cord 32 (toreturn the lever 44 and actuators 48 to their normal positions)consequently has no effect on the continued operation of the blowermotor through the timed cycle.

In general, the blower is operated by the time delay relay 76 for aperiod sufficient to convey an amount of lightweight materials from thehopper 14 to fill or replenish the capacity of the screened reservoir atthe involved discharge outlet. Ordinarily, such period of operation maybe of relatively short duration, ranging from a few seconds up to,perhaps, 30 seconds. The exact period of blower operation will depend,of course, upon the size and length of the screen section 28, the sizeand power of the blower, and the character and bulk density of thelightweightmaterials being conveyed. The indicated range generallyrelates to the conveyance and distribution of lightweight cellularpacking materials (e.g., foamed, expanded polystyrene) and similarlightweight materials, in plant filling and/or packaging operations.

It will be appreciated that the blower motor operates only upon demand,as described above, and then only for the very brief period required toreplenish the supply at a particular distribution outlet. As aconsequence, the period of time during which noise of the blower is adisturbing element is substantially reduced, if not virtuallyeliminated. In a typical operation, for example, the blower operationmay range to a few minutes of time in an entire days operation. 'Afurther advantage is that each filling operation automatically occursonly with respect to a single column, upon demand of the operator, withno possibility of conflict through simultaneous demand fromseparatedistribution stations.

The overall operation of the above described system of apparatus, in atypical filling or packaging operation, is briefly summarized below:

As noted, the conveyance system is normally at rest, with the blowermotor off and each distribution column 28 filled with a supply ofpackaging material. In thid condition, the operators at the variouspackaging stations can dispense packaging materials through theirrespective valve outlets 30, as needed. At such' time as a particulardistribution column becomes substantially empty, through continued use,the operator at such station can replenish the supply by the simpleexpedient of pulling the cord 32 to initiate the controlled delivery ofa predetermined quantity of replacement material to his dispensingstation. This operation results through pivoting of the lever 44 toinitiate movement of the flap means 40 from its rest position shown inFIG. 2 to the gas diverting position shown in FIG. 3. Pivoting of thelever 44 simultaneously causes switch 66 on pivot shaft 46 to close thetimer contacts at 80, through actuation of the time control relay 76.This in turn starts the blower motor 72 through actuation of the starterrelay 74, thereby initiating and maintaining the timed delivery cyclefor feeding lightweight material from the sup ply hopper 14 to thestation indicating the exhausted supply. Sequentially, upward pivotingof the flap means 40 causes the normally closed switch 64 to open,thereby breaking the circuit through switch 66 and locking out all othercircuits. Upon return of the lever 44 to its normal position (throughrelease of the cord 32) switch 66 again opens, maintaining thelocked-out condition of the other circuits. At the end of the timedcycle of delivery by the blower 20, the blower operation stops and theconveyance system reverts to its normal rest condition.

From the foregoing, it will be apparent that the system of apparatus andthe method of the present invention make possible the rapidreplenishment anddelivcry of a predetermined quantity of lightweightmaterial to a particular distribution outlet, while avoiding theproblems arising from simultaneous demand from different distributionoutlets. The system thus effects a controlled delivery to a singledistribution outlet, providing control over the amount delivered througha timed delivery cycle, in response to .the demand of an operator atsuch outlet. The present invention also enable such results to beobtained with virtual elimination of noise from the blower motor, exceptduring the very short interval of demand and replenishment at aparticular distribution station. The system also lends itself toplacement of the blower motor and supply hopper at a remote locationwith respect to the filling or discharge operations, for example, as inFIG. 1, thus additionally reducing or virtually eliminating any noiseproblems associated with operation of the blower.

It will be understood that many variations are possible in the methodand apparatus described, without departing from the scope of theinvention. To illustrate, while an automatically timed period ofoperation of the blower has been described and illustrated, theinvention is clearly not limited to such automatic timing, and manualtiming could be substituted with equal facility. For example, thecontrol circuit could be designed to operate by holding the pull cord inthe depressed position throughout the replenishment cycle, the controlcycle then being timed manually by the operator. To those skilled in theart to which this invention pertains, the foregoing and other similarvariations are clearly within the scope of the invention, the disclosureherein being intended to be purely illustrative rather than limiting.

I claim:

1. In a system for the pneumatic conveyance and selective distributionof lightweight subdivided materials to a plurality of gas dissipatingdistribution outlets, control means operable upon demand to effectdelivery of a predetermined quantity of said lightweight material to apreselected distribution outlet, said control means inclu dinggasdiverting flap means mounted within substantially closed conduit meansforming part of said conveyance system, blower means introducingconveyance gas to said closed conveyance system, said flap means beingpositioned adjacent each said gas dissipating distribution outlet tonormally seal and close the same, lever means to pivot each said flapmeans to a position within said closed conduit means where it divertsconveyance gas for dissipation through the adjacent distribution outlet,said flap means being of a configuration to be held open in said gasdiverting position by the movement and pressure of said conveyance gas,and means responsive to movement of the lever means at said preselecteddistribution outlet to initiate a controlled operation of said blowermeans to deliver light weight material and conveyance gas only to saidpreselected gas dissipating distribution outlet.

2. A system as in claim 1 including a timer control for said blowermeans, responsive to operation of said switch means. I

3. A system as in claim 1 wherein biasing means are provided to normallyhold said lever means in inoperative position.

4. A system as in claim 1 wherein said control means includes manuallyoperable means at said preselected gas dissipating distribution outletto actuate and shift said lever means.

5. A system as in claim 1 wherein each of said gas dissipatingdistribution outlets is in the form of an elongated conduit formed ofscreening means and having a volume sufficient to receive saidpredetermined quantity of lightweight material.

6. In a system for the pneumatic conveyance and selective distributionof lightweight subdivided materials to a plurality of gas dissipatingdistribution outlets, control means to effect delivery of apredetermined quantity of said lightweight material to a singledistribution outlet preselected from a plurality of such distributionoutlets, said control means including pivotally mounted flap meansadjacent each of said gas dissipating distribution outlets, blower meansadapted to introduce conveyance gas to said closed conveyance system,each of said flap means being positioned in said closed conveyancesystem immediately adjacent but downstream from a gas dissipatingdistribution outlet as respects a point of introduction of conveyancegas from said blower means, lever means to pivot each of said flap meansfrom a normal position sealing a distribution outlet to an operableposition diverting conveyance gas for dissipation and discharge throughsuch distribution outlet, said flap means being of a configuration to beheld open in said gas diverting position by the movement and pressure ofsaid conveyance gas, first switch means at each distribution outlet forenergizing a timer control for said blower means, second switch means ateach gas dissipating distribution outlet for deenergizing the switchmeans at all other distribution outlets, and means interconnecting thelever means and switch means at each gas dissipating distributionoutlet, whereby actuating the lever at a preselected gas dissipatingdistribution outlet serves to initiate a timed sequence of the blowermeans to convey a predetermined quantity of said lightweight material tosaid preselected tion of the first and second switch means at eachdistribution outlet.

8. A system as in claim 7 wherein said means to effect sequentialoperation of said switch means includes mechanical means to effect atime delay in the operation thereof.

9. A system as in claim 6 wherein each of said lever means is providedwith biasing means to hold the same in a normally inoperative position.

20. A system as in claim 6 wherein said first switch means is normallyin open position and each of said second switch means is normally inclosed position.

11. A system as in claim 6 wherein each of said first and second switchmeans is mounted for actuation by pivotal movements of said lever means.

12. A system as in claim 11 wherein each of said switch means is gravityactuated, and said first and second switch means are mounted withrespect to said lever means to provide a time delay between actuation ofsaid first switch means and actuation of said second switch means.

13. In a system for the pneumatic conveyance and selective distributionof lightweight subdivided materials to plural distribution outlets,control means to effect delivery of a predetermined quantity of saidlightweight material to a single distribution outlet preselected from aplurality of such distribution outlets, said control means including apivotally mounted flap means adjacent each of said distribution outlets,blower means adapted to introduce conveyance gas to said closedconveyance system, each of said flap means being positioned in saidclosed conveyance system immediately adjacent but downstream from adistribution outlet as respects a point of introduction of conveyancegas from said blower means, lever means to pivot each of said:

flap means from a normal position sealing a distribution outlet to anoperable position diverting conveyance gas to such distribution outlet,first gravity actuated switch means at each distribution outlet forenergizing a timer control for said blower means, second gravityactuated switch means at each distribution outlet for deenergizing theswitch means at all other distribution outlets, said first and secondswitch means being mounted with respect to said lever means to provide atime delay between actuation of said first switch means and actuation ofsaid second switch means, said time delay being obtained by a slidingpivotal contact between said lever means and separate actuating meansfor said flap means, and means interconnecting the lever means andswitch means at each distribution outlet, whereby actuating the lever ata preselected distribution outlet serves to initiate a timed sequence ofthe blower means to convey a predetermined quantity of said lightweightmaterial to said preselected distribution outlet, while simultaneouslypreventing conveyance of said lightweight material to said otherdistribution outlets.

14. In a method for effecting delivery of a predetermined quantity oflightweight subdivided materials to a preselected gas dissipating outletin a pneumatic conveyance system having a plurality of gas dissipatingdistribution outlets, the steps of providing a source of gas underpressure, introducing gas from said source to a generally closedconveyance system to provide a stream of conveyance gas in said system,diverting lightweight subdivided material from a source of such materialinto said stream of conveyance gas at a substantially uniform rate perunit of time, said conveyance gas being introduced to said generallyclosed conveyance system in response to a signal from a prese' lecteddistribution outlet, simultaneously diverting gas introduced from saidsource only through said preselected gas dissipating distribution outletwhile preventing diversion of said gas through nonselected distributionoutlets, and controlling the duration of a gas introduction on a timedcycle in response to said signal, whereby a quantity of said lightweightmaterial determined by the period of said timed cycle is caused to bemoved with said stream of conveyance gas and to be conveyed in saidsystem to said preselected gas dissipating distribution outlet.

15. A method as in claim 14 wherein said diversion of gas from saidpressurized source through said preselected distribution outlet iseffected by a timed diversion of of substantially all of the gas flowthrough said preselected gas dissipating distribution outlet.

1. In a system for the pneumatic conveyance and selective distributionof lightweight subdivided materials to a plurality of gas dissipatingdistribution outlets, control means operable upon demand to effectdelivery of a predetermined quantity of said lightweight material to apreselected distribution outlet, said control means including gasdiverting flap means mounted within substantially closed conduit meansforming part of said conveyance system, blower means introducingconveyance gas to said closed conveyance system, said flap means beingpositioned adjacent each said gas dissipating distribution outlet tonormally seal and close the same, lever means to pivot each said flapmeans to a position within said closed conduit means where it divertsconveyance gas for dissipation through the adjacent distribution outlet,said flap means being of a configuration to be held open in said gasdiverting position by the movement and pressure of said conveyance gas,and means responsive to movement of the lever means at said preselecteddistribution outlet to initiate a controlled operation of said blowermeans to deliver light weight material and conveyance gas only to saidpreselected gas dissipating distribution outlet.
 2. A system as in claim1 including a timer control for said blower means, responsive tooperation of said switch means.
 3. A system as in claim 1 whereinbiasing means are provided to normally hold said lever means ininoperative position.
 4. A system as in claim 1 wherein said controlmeans includes manually operable means at said preselected gasdissipating distribution outlet to actuate and shift said lever means.5. A system as in claim 1 wherein each of said gas dissipatingdistribution outlets is in the form of an elongated conduit formed ofscreening means and having a volume sufficient to receive saidpredetermined quantity of lightweight material.
 6. In a system for thepneumatic conveyance and selective distribution of lightweightsubdivided materials to a plurality of gas dissipating distributionoutlets, control means to effect delivery of a predetermined quantity ofsaid lightweight material to a single distribution outlet preselectedfrom a plurality of such distribution outlets, said control meansincluding pivotally mounted flap means adjacent each of said gasdissipating distribution outlets, blower means adapted to introduceconveyance gas to said closed conveyance system, each of said flap meansbeing positioned in said closed conveyance system immediately adjacentbut downstream from a gas dissipating distribution outlet as respects apoint of introduction of conveyance gas from said blower means, levermeans to pivot each of said flap means from a normal position sealing adistribution outlet to an operable position diverting conveyance gas fordissipation and discharge through such distribution outlet, said flapmeans being of a configuration to be held open in said gas divertingposition by the movement and pressure of said conveyance gas, firstswitch means at each distribution outlet for energizing a timer controlfor said blower means, second switch means at each gas dissipatingdistribution outlet for de-energizing the switch means at all otherdistribution outlets, and means interconnecting the lever means andswitch means at each gas dissipating distribution outlet, wherebyactuating the lever at a preselected gas dissipating distribution outletserves to initiate a timed sequence of the blower means to convey apredetermined quantity of said lightweight material to said preselecteddistribution outlet, while simultaneously preventing conveyance of saidlightweight material to said other gas dissipating distribution outlets.7. A system as in claim 6 wherein said control means includes circuitmeans interconnecting a power source for said blower means with each ofsaid first and second switch means, and means to effect a sequentialoperation of the first and second switch means at each distributionoutlet.
 8. A system as in claim 7 wherein said means to effectsequential operation of said switch means includes mechanical means toeffect a time delay in the operation thereof.
 9. A system as in claim 6wherein each of said lever means is provided with biasing means to holdthe same in a normally inoperative position.
 10. A system as in claim 6wherein said first switch means is normally in open position and each ofsaid second switch means is normally in closed position.
 11. A system asin claim 6 wherein each of said first and second switch means is mountedfor actuation by pivotal movements of said lever means.
 12. A system asin claim 11 wherein each of said switch means is gravity actuated, andsaid first and second switch means are mounted with respect to saidlever means to provide a time delay between acTuation of said firstswitch means and actuation of said second switch means.
 13. In a systemfor the pneumatic conveyance and selective distribution of lightweightsubdivided materials to plural distribution outlets, control means toeffect delivery of a predetermined quantity of said lightweight materialto a single distribution outlet preselected from a plurality of suchdistribution outlets, said control means including a pivotally mountedflap means adjacent each of said distribution outlets, blower meansadapted to introduce conveyance gas to said closed conveyance system,each of said flap means being positioned in said closed conveyancesystem immediately adjacent but downstream from a distribution outlet asrespects a point of introduction of conveyance gas from said blowermeans, lever means to pivot each of said flap means from a normalposition sealing a distribution outlet to an operable position divertingconveyance gas to such distribution outlet, first gravity actuatedswitch means at each distribution outlet for energizing a timer controlfor said blower means, second gravity actuated switch means at eachdistribution outlet for de-energizing the switch means at all otherdistribution outlets, said first and second switch means being mountedwith respect to said lever means to provide a time delay betweenactuation of said first switch means and actuation of said second switchmeans, said time delay being obtained by a sliding pivotal contactbetween said lever means and separate actuating means for said flapmeans, and means interconnecting the lever means and switch means ateach distribution outlet, whereby actuating the lever at a preselecteddistribution outlet serves to initiate a timed sequence of the blowermeans to convey a predetermined quantity of said lightweight material tosaid preselected distribution outlet, while simultaneously preventingconveyance of said lightweight material to said other distributionoutlets.
 14. In a method for effecting delivery of a predeterminedquantity of lightweight subdivided materials to a preselected gasdissipating outlet in a pneumatic conveyance system having a pluralityof gas dissipating distribution outlets, the steps of providing a sourceof gas under pressure, introducing gas from said source to a generallyclosed conveyance system to provide a stream of conveyance gas in saidsystem, diverting lightweight subdivided material from a source of suchmaterial into said stream of conveyance gas at a substantially uniformrate per unit of time, said conveyance gas being introduced to saidgenerally closed conveyance system in response to a signal from apreselected distribution outlet, simultaneously diverting gas introducedfrom said source only through said preselected gas dissipatingdistribution outlet while preventing diversion of said gas throughnonselected distribution outlets, and controlling the duration of gasintroduction on a timed cycle in response to said signal, whereby aquantity of said lightweight material determined by the period of saidtimed cycle is caused to be moved with said stream of conveyance gas andto be conveyed in said system to said preselected gas dissipatingdistribution outlet.
 15. A method as in claim 14 wherein said diversionof gas from said pressurized source through said preselecteddistribution outlet is effected by a timed diversion of of substantiallyall of the gas flow through said preselected gas dissipatingdistribution outlet.